Breast Imaging: A Core Review (41 page)

A. The MGD increases by 16%.

B. The MGD decreases because of the higher kVp.

C. The MGD increases by 60%.

D. The MGD increases by more than 60% because of the increased penetration at higher kV.

E. The MGD increases by <60% because of the increased penetration at higher kV.

9
 Which material is least likely to be used in a mammography x-ray detector?

A. Csl

B. Nal

C. BaFBr

D. Se

10
 The soft tissue thickness (cm) that attenuates half the x-ray beam is likely:

A. 0.5

B. 1

C. 2

D. 3

11
 Which voltage (kV) would likely be used to image a dense 7-cm breast?

A. 20

B. 25

C. 32

D. 40

12
 Which value is least likely in a magnification mammogram?

A. Focus 0.1 mm

B. Voltage 28 kV

C. Current 100 mA

D. Exposure 3 seconds

13
 For a fixed mAs and at a constant kVp, a significant increase in exposure time will cause:

A. A significant increase in radiation exposure to the breast

B. A significant change in the level required for proper viewing if the window is the same as for the first exposure

C. An increase in blur due to motion

D. An increased likelihood of damage to the detector

E. An increased heat load on the x-ray tube

14
 Microcalcifications that can readily be seen on a mammogram would likely not be visible at all on a chest radiograph. The most important reason for this is:

A. The large region of coverage of the chest radiograph

B. The obfuscation of the microcalcifications by the spine

C. The large drop in the attenuation coefficient of calcium for the chest radiograph

D. The large drop in the attenuation coefficient of soft tissue for the chest radiograph

E. The large increase in exposure time required for the chest radiograph

15
 A grid is not used in magnification mammography. This is primarily because:

A. Grids are not used at all in mammography

B. The grid would be visible in the image due to the use of the small focal spot

C. The grid would be visible in the image due to the increase in contrast occurring in magnification mammography

D. Adding a grid would increase the dose without significantly reducing scatter

E. Without the pressure of the compressed breast on the detector, the moving grid would vibrate too freely

16
 In magnification mammography, the small focal spot is almost always used, whereas for contact mammography and for the same patient, the large focal spot is the norm. Why?

A. We can tolerate the longer exposure time required for the small focal spot because magnification reduces the effect of motion.

B. The reduction in exposure rate tolerated by the small focal spot is compensated by removal of the grid.

C. In magnification, a smaller region of the breast is imaged and therefore not as much radiation is required.

D. Compression is not used for magnification and thus less radiation is needed to capture the magnified region of interest.

E. Because the image is magnified, a higher level of noise is acceptable, and thus, the smaller focal spot can still deliver enough radiation in a short enough period of time (even though the radiation rate is reduced).

17
 The tube voltage is generally set higher for thicker breasts. The
primary
reason for doing so is:

A. To reduce exposure time, thereby decreasing motion artifacts

B. To reduce radiation dose by increasing the penetration

C. To improve tissue contrast

D. To improve the spatial resolution of the image

E. To reduce the scatter by increasing the amount of energy per photon

18
 The compressed breast is estimated to almost 5-cm thickness. The mean glandular dose (MGD) for a cranio-caudal view is lowest for which type of mammography system?

A. Film-screen

B. Computed radiography

C. Direct digital radiography

D. Xeroradiography.

19
 When compared to routine screening mammography, magnification views have which of the following?

A. Less contrast

B. Less motion blur and less scatter

C. Longer exposure time

D. More scatter and less motion blur

E. More noise

F. Longer source-to-object distance

20
 Breast compression increases which of the following?

A. Scatter

B. Breast thickness

C. Noise

D. Image contrast

21
 The mammography operators are required to be monitored for radiation exposure by state regulations. A female technologist declares she is pregnant. What is the applicable occupational dose limit?

A. Same as a nonpregnant x-ray technologist

B. 100 millirems to the fetus

C. 500 millirems to the fetus

D. 5,000 millirems per year

22
 Thyroid shielding during mammography should be used:

A. Always

B. Only for women of reproductive capacity

C. Only upon request

D. Never

23
 Which x-ray target and filter combination is best to image a thicker (7 cm), dense breast?

A. Molybdenum target/molybdenum filter

B. Molybdenum target/rhodium filter

C. Rhodium target/rhodium filter

D. Tungsten target/rhodium filter

24
 Which of the following is an advantage of screen-film mammography over digital mammography?

A. Improved throughput

B. Improved latitude

C. Higher spatial resolution

D. Decreased dose for comparable image quality

E. Image processing and digital archival

25
 For a 4-cm breast with a composition ratio of 50% glandular to 50% adipose, the magnitude of dose reduction achievable for comparable image quality in the transition from screen/film to digital mammography is approximately:

A. 10%

B. 20%

C. 40%

D. 60%

E. 80%

26
 In digital mammography, the approximate mean glandular dose (MGD) for a 5-cm thick average density breast imaged using automatic exposure control with a W/Rh target/filter combination would be closest to:

A. 100 millirads

B. 100 millisieverts

C. 2 milligray

D. 300 millirads

27
 The technique factor that has the strongest impact on digital mammography image quality is:

A. Target/filter combination

B. Focal spot size

C. mAs

D. Field size

E. kVp

28
 In a digital mammography image, electronic magnification:

A. Results in reduced image noise

B. Leaves the spatial resolution unchanged

C. Lowers the needed radiation dose

D. Is the same as geometric magnification

29
 What grid ratio range is used for full-field digital mammography (FFDM)?

A. 9:1 to 8:1

B. 8:1 to 7:1

C. 7:1 to 6:1

D. 3:1 to 6:1

E. 3:1 to 5:1

30
 What focal spot size is used for a standard mammogram (CC and MLO)?

A. 0.1 mm

B. 0.2 mm

C. 0.3 mm

D. 0.4 mm

E. 0.5 mm

31
 What is the recommended source to image distance (SID) for mammography?

A. 10 to 50 cm

B. 20 to 50 cm

C. 30 to 60 cm

D. 40 to 50 cm

E. 50 to 80 cm

32
 What focal spot size is used for magnification imaging in mammography?

A. 0.1 mm

B. 0.2 mm

C. 0.3 mm

D. 0.4 mm

E. 0.5 mm

33
 What is the reason interpretation of digital mammography images should be done on a 5 megapixel monitor?

A. Ghost image factor

B. Improved resolution

C. Improved contrast

D. Uniformity rule

E. Phosphor light transmission

34
 MQSA requirement for collimation test states that the x-ray field may not extend beyond any edge of the image receptor by more than what percentage of the source-to-image (SID)?

A. 0.5%

B. 1.5%

C. 2.0%

D. 3.5%